Given the uncertainties about Trump punters should read the bookie market rules

This is for the £56m next President market on Betfair:-

“Who will be elected to be the next President of the United States of America as a result of the 2016 presidential election?

This market will be turned in-play at the stated time on the day of the election. Thereafter the market will not be actively managed. Customers are entirely responsible for their bets at all times.

This market will be settled according to the candidate that has the most projected Electoral College votes won at the 2016 presidential election. Any subsequent events such as a ‘faithless elector’ will have no effect on the settlement of this market. In the event that no Presidential candidate receives a majority of the projected Electoral College votes, this market will be settled on the person chosen as President in accordance with the procedures set out by the Twelfth Amendment to the United States Constitution.

This market will be void if an election does not take place in 2016. If more than one election takes place in 2016, then this market will apply to the first election that is held.

If there is any material change to the established role or any ambiguity as to who occupies the position, then Betfair may determine, using its reasonable discretion, how to settle the market based on all the information available to it at the relevant time. Betfair reserves the right to wait for further official announcements before the market is settled..”